4.2L Inline Straight Six Cylinder PCM Description
The powertrain has electronic controls to reduce exhaust emissions while maintaining excellent driveability and fuel economy. The powertrain control module (PCM) is the control center of this system. The PCM monitors numerous engine and vehicle functions. The PCM constantly looks at the information from various sensors and other inputs, and controls the systems that affect vehicle performance and emissions.
The PCM also performs the diagnostic tests on various parts of the system. The PCM can recognize operational problems and alert the driver via the malfunction indicator lamp (MIL). When the PCM detects a malfunction, the PCM stores a diagnostic trouble code (DTC). The problem area is identified by the particular DTC that is set. The control module supplies a buffered voltage to various sensors and switches. Review the components and wiring diagrams in order to determine which systems are controlled by the PCM.
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The following are some of the functions that the PCM controls:
- The Idle air control motor (IAC)
- The EVAP purge solenoid
- The electronic transmission controls
- The A/C relay
- The cooling fan relay
- The VSS output
- The Secondary air injection system (AIR) (if equipped)
- The MIL control
- The cruise control inhibit
- The Exhaust camshaft actuator (Variable Valve Timing)
Powertrain Control Module Function The powertrain control module (PCM) constantly looks at the information from various sensors and other inputs and controls systems that affect vehicle performance and emissions. The PCM also performs diagnostic tests on various parts of the system. The PCM can recognize operational problems and alert the driver via the malfunction indicator lamp (MIL). When the PCM detects a malfunction, the PCM stores a diagnostic trouble code (DTC).
